Thermally insulated container

ABSTRACT

The present invention provides a thermally insulated shipping container 1 comprising a thermally insulating layer 5 defining a first void, a main layer 9, 10, 11 containing phase change material (main PCM layer) within the first void and defining a second void within the first void, a barrier layer 12 containing phase change material (barrier PCM layer) within the second void and distinct from the main PCM layer, the barrier PCM layer 12 defining a third void within the second void, the container being arranged to receive a product for transportation inside of the third void, wherein the main PCM layer 9, 10, 11 has an average thickness greater than the average thickness of the barrier PCM layer 12, the barrier PCM layer 12 comprises of an envelope in which the phase change material of the barrier PCM layer 12 is contained and the barrier PCM layer 12 is configured to maintain the phase change material with a relatively even distribution within the envelope.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.16/305,765, filed Nov. 29, 2018. U.S. application Ser. No. 16/305,765 isincorporated here by reference in its entirety to provide continuity ofdisclosure.

FIELD OF THE INVENTION

The present invention relates to thermally insulated containers andparticularly, but not exclusively, to passive insulated shippingcontainers of the type used for transporting medicinal products, or thelike, which have to be maintained during transportation at a relativelyconstant low temperature but above freezing, typically in the range of 2to 8° C. This is necessary to prevent the product from being damaged, orits shelf life being reduced relatively to the shelf life stated on theproduct.

BACKGROUND OF THE INVENTION

Passive insulated shipping containers typically comprise an insulatedcontainer comprising an insulating outer casing which is lined with, orhouses, a number of cool blocks, cool trays, gel packs, cool bricks orsimilar, which for the purposes of the present specification arecollectively referred to as cool packs. These may be cooled until aphase change occurs in the phase change material in the cool packs, froma liquid to a solid, so that the subsequent phase change back from asolid to a liquid acts to maintain the contents of the container at aconstant temperature. Examples of materials which change state from asolid to a liquid to produce a cooling effect are paraffin wax andwater-based solutions.

Passive insulated shipping containers may comprise a container havingthree layers, an outer insulating layer, typically formed from expandedfoam, an inner layer of cool packs and an intervening layer between theouter and inner layers made up of a number of vacuum insulation panelsto provide enhanced insulation. The container may further comprise anouter casing to provide protection for the outer insulating layer duringtransportation and/or an inner lining.

Regardless of the particular construction of a passive insulatedshipping container, most utilise the above described cool packs and thephase change that occurs in the material in these, to maintain theproduct at the correct temperature during transportation. This normallyrequires that the cool packs be chilled separately from the container inorder for the phase change to occur, to charge the cool packs ready foruse. If the cool packs are chilled at 0° C. or a few degrees below thenthe time for which they require to be chilled, thus the storage spacerequired to chill them, is far greater than it would be if they werechilled, for example, at −18° C. However, when the cool packs arechilled at such low temperatures, before the cool packs can be used itis first normally necessary that they be brought up to about 0° C., forotherwise inserting these directly into a container and then insertingproduct in that container could result in a product (at least locally)being chilled to below 0° C. (or some other temperature at which theproduct would be destroyed).

When using cool packs in passive insulated shipping containers, asdescribed above, cool packs are normally chilled to about −18° C. andthen brought back up to typically 5° C., prior to packing. This normallyinvolves double handling of the cool packs, first chilling them to −18°C. and then subsequently bringing them up to 5° C. and arrangingsuitable storage for them. This is time consuming and may also result incool packs not being available for use at short notice.

SUMMARY OF THE INVENTION

According to the present invention there is provided a thermallyinsulated container comprising a thermally insulating layer defining afirst void, a main layer containing phase change material (main PCMlayer) within the first void and defining a second void within the firstvoid, a barrier layer containing phase change material (barrier PCMlayer) within the second void and distinct from the main PCM layer, thebarrier PCM layer defining a third void within the second void, thecontainer being arranged to receive a product for transportation insideof the third void, wherein the main PCM layer has an average thicknessgreater than the average thickness of the barrier PCM layer and beingcharacterised in that the barrier PCM layer comprises of an envelope inwhich the phase change material of the barrier PCM layer is containedand the barrier PCM layer is configured to maintain the phase changematerial with a relatively even distribution within the envelope.

The present invention provides a barrier PCM layer between the main PCMlayer and the product. This barrier PCM layer may be relatively thincompared to the main PCM layer and it may be stored at room temperature.The barrier PCM layer provides a barrier between the main PCM layer anda product inserted into the container and may permit the PCM layer,possibly in the form of cool packs, to be inserted into the container at−18° C., or some other temperature below the temperature at which isdesired that the product be transported. Alternatively, the containerwith the main PCM layer installed in it, could be chilled to −18° C., orsome other temperature below the temperature at which the product is tobe transported. In either case, the barrier PCM layer may be arranged tohave a volume and latent heat of fusion to bring the main PCM layer upto the temperature at which the main PCM layer starts to change phase,which may be in the range 0 to 8° C. An advantage of this is that itpermits cool packs of a main PCM layer, chilled to −18° C. or similar,to be immediately placed with the barrier PCM layers (possibly stored atroom temperature) and the product into the container for shipment,whilst ensuring the product does not drop below a specified temperature.This permits a thermally insulated container be prepared for use atshort notice and also avoids double handling of the main PCM layer.

The provision of the barrier PCM layer need not add to the overall massof PCM material within a container. The barrier PCM layer and the phasechange material therein, will itself become “charged”, (in providingenergy to the main PCM layer) and will thus then subsequently absorbenergy and thus act to maintain the product at the desired temperature.This will thus reduce the quantity of PCM material required for the mainPCM layer. Alternatively, the additional barrier PCM layer will add tothe performance of the container, for in transferring energy to the mainPCM layer, the barrier PCM layer will subsequently be able to absorbenergy entering the container, thus increase the performance of thecontainer.

With the present invention, the barrier PCM layer comprises an envelopein which the phase change material of the barrier PCM layer is containedand the barrier PCM layer is configured to maintain the phase changematerial evenly distributed within the envelope. By arranging for thebarrier PCM layer to maintain the phase change material with arelatively even distribution within the envelope, it is possible for theenvelope to be both relatively thin and to be flexible, whilst stillmaintaining an even distribution of the phase change material and thusprotecting the product from local damage from the adjacent main PCMlayer.

In one aspect of the invention, the envelope is advantageously formedfrom two sheets of flexible material bonded (which term includesadhering, welding or any other similar joining technique) together todivide the envelope into the plurality of discrete pockets. Thisprovides both a relatively easy and economical way of forming thebarrier PCM layer and may provide a flexible PCM barrier layer which mayeasily be placed around a product or which may be used to line a voidformed by the main PCM layer, into which a product is to be placed.

The provision of a flexible envelope is particularly advantageousbecause, unlike the main PCM layer which in use will be rigid due to thePCM layer being in a solid phase, the phase change material of thebarrier PCM layer will be in its liquid phase when the barrier PCM layeris placed in the container. Thus, if the envelope is flexible, it willbe possible to line the void in the container with it, the envelopeconforming to the sides of the void and thus minimising the spaceoccupied by the envelope. Additionally, the envelope may be folded,permitting a single envelope to line multiple sides, base or top of thevoid in the container.

As an alternative to the above arrangement, or in addition thereto, thebarrier PCM layer may be configured to maintain the phase changematerial with a relatively even distribution within the envelope, byfurther comprising a capillary sheet within the envelope, whichcapillary sheet is formed of a material which exhibits a capillaryaction on the phase change material within the envelope. In this mannerthe capillary sheet may ensure an even distribution of the phase changematerial within the envelope, or within pockets of the envelope, of thePCM barrier layer, again avoiding the requirement that the barrier PCMlayer comprise cool packs, or similar, which are retained in position bybeing rigid.

Preferably the capillary sheet within the envelope is between 5 mm and10 mm thick. This may be arranged to hold sufficient phase changematerial to absorb any thermal shock which would otherwise be imposed ona product by chilled cool packs of the main PCM layer, whilst not beingof a sufficient thickness to prevent the barrier PCM layer beingflexible. Again, the envelope may preferably be formed from two sheetsof flexible material bonded together and with the capillary sheettherein.

The main PCM layer may comprise one or more cool packs containing phasechange material, which cool packs are formed of a different material tothe material of the envelope and which are substantially more rigid thanthe envelope. The relatively rigid cool packs of the main PCM layerensures that the cool packs maintain an appropriate shape when theliquid PCM material within them solidifies. This is necessary to ensurethat they can then be appropriately arranged within the container.However, as mentioned above, this is not necessary in the case of theenvelope, for any phase change from a liquid to a solid of the phasechange material within the envelope, will only occur only after theenvelope has been installed within the container.

The main PCM layer preferably comprises a plurality of cool packs eachcontaining phase change material, which cool packs are formed of adifferent material to the envelope and are substantially more rigid thanthe envelope, with packs corresponding to each of four sides and a baseof the container. In this way the packs of the main PCM layer can beused to define the void in which the flexible envelope of the barrierPCM layer is to be inserted.

Preferably, at least some cool packs of the main PCM layer are separatefrom each other. However, some cool packs may be joined together toassist in assembly within the container.

The barrier PCM layer may comprise at least four joined togetherenvelopes, one corresponding to each of the four sides of the container,it may comprise five joined together envelopes, one corresponding toeach other four sides and the base of the container, or it may comprisesix joined together envelopes, one corresponding to each of the foursides of the container, one to the base and one to the lid of thecontainer. In this last case, because the barrier PCM layer is flexible,a product may subsequently be inserted into the container by theenvelope forming a lid of the barrier PCM layer being folded open topermit the product to be loaded.

Each of the envelopes may be formed separately and subsequently joinedto an adjacent envelope by being welded or otherwise bonded to thatenvelope. Alternatively all the envelopes may be formed from two sheetsof flexible material bonded together to define said envelopes, with thebonds forming living hinges to permit adjacent envelopes to be foldedrelative to each other to a shape substantially corresponding to that ofthe second void of the container. As a further alternative, a singleenvelope may be shaped to correspond to multiple sides, with theenvelope then being folded to form appropriate panels to line the mainPCM layer.

The two sheets of the envelope may be formed from vinyl and this, in oneembodiment, may house a polyamide/polyethylene laminate pouch containinga capillary sheet and a phase change material, with the two vinyl sheetsbeing bonded together by being heat or radio frequency welded.

The phase change material of the main PCM layer may be the same as thephase change material of the barrier PCM layer, in which case it ispreferable the volume of the phase change material of the barrier PCMlayer is between 8 to 36% (more preferably between 12% and 22%) of thevolume of the phase change material of the main PCM layer. A ratio ofthe volumes in these ranges will normally be sufficient for the barrierPCM layer (at room temperature) to provide sufficient energy to increasethe temperature of the phase change material of the main PCM layer fromaround −18° C. to above 0° C.

For the same reasoning and regardless of whether or not the phase changematerial of the PCM barrier layer is the same as the phase changematerial of the main PCM layer, it is preferable that the latent heat offusion of the phase change material multiplied by the volume of thephase change material of the barrier PCM layer is between 8% and 36%(more preferably between 12% and 22%) of the latent heat of fusion ofthe phase change material multiplied by the volume of the phase changematerial of the main PCM layer.

The thermally insulated container may comprise a lining within the thirdvoid. The thermally insulating layer may comprise a layer of expandedfoam or a layer of vacuum insulation panels or a combination of the two,normally with the vacuum insulation panels located inwardly of a layerof expanded foam. Additionally the container may comprise an outer,possibly corrugated, layer to provide protection to the thermallyinsulating layer.

According to a second aspect of the invention there is provided a methodof transporting a product at a relatively constant temperature themethod comprising the steps of obtaining a container in accordance withthe invention as described above, chilling the main PCM layer to below−14° C., placing the barrier PCM layer at a temperature above 4° C. intothe second void defined by the main PCM layer and placing product to betransported into the third void.

The method may further comprise chilling the main PCM layer to below−14° C. and subsequently inserting it into the second void of thecontainer prior to inserting the barrier PCM layer. This may enable thebarrier PCM layer to be inserted at room temperature.

One embodiment of the present invention will now be described, by way ofexample only, with reference to the accompanying figures of which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view through a thermally insulated shippingcontainer in accordance with the present invention;

FIG. 2 is a plan view of a barrier PCM layer of the thermally insulatedshipping container of FIG. 1; and

FIG. 3 is a plan view of an alternative barrier PCM layer of thethermally insulated shipping container of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, this is a section through a thermally insulatedshipping container, indicated generally as 1. The container of FIG. 1has equivalent components lining all four walls and thus, with theexception of the lids 3, 4, and 14, a section taken orthogonal to thesection shown in FIG. 1 will show equivalent components to those shownin FIG. 1.

The container 1 comprises an outer box 2 formed of corrugated board, forexample corrugated cardboard or corrugated plastic, with two flaps 3 and4 located on an upper edge of the box 2.

Inside the outer box 2 is a thermally insulating box 5, formed frommoulded polystyrene, which thermally insulating box 5 is five sided withan open top. The four inner side walls and base of the thermallyinsulating box 5 may additionally be lined with vacuum insulation panels6, to improve the thermal insulating performance of the container 1.

The vacuum insulation panels 6 are relatively delicate and easy topuncture and the container 1 has a clear plastic sheet 7 of, forexample, amorphous polyethylene tetraphalate (a PET), to protect thevacuum insulation panels 6. This is formed in to the shape of fiveadjoining panels and is folded to line the faces of all the five vacuuminsulation panels 6 within the container 1 and to fold over the upperedges, as shown at 8, and over the outer surfaces of the vacuuminsulation panels 6 of the side walls of the container 1. The componentsthus far describe will normally be installed in the container 1 by themanufacturer.

The container additionally comprises a main layer of phase changematerial (main PCM layer) consisting of four wall cool packs 9 (only twoof which are shown), a base cool pack 10 and a top cool pack 11. The topcool pack 11 is arranged to, in use, sit on and be supported by the topedges of the four wall cool packs 9. Each of the cool packs 9, 10, 11comprises a rigid casing of high density polyethylene, filled with thephase change material Tetradecane.

The container 1 additionally comprises a barrier layer 12 of phasechange material (barrier PCM layer), which may be in either one of thetwo alternative forms described below with reference to FIGS. 2 and 3.The barrier PCM layer 12 is preformed into six panels, as describedbelow, so that it may be inserted into the void formed by the cool packs9 and 10, so as to line all five inner surfaces of the cool packs 9 and10 and to also form a lid portion 14, as shown. The inner surface of thebarrier PCM layer defines a further void 13 in which a product (notshown) to be transported is to be placed.

Referring now to FIGS. 2 and 3, the barrier PCM layer, indicatedgenerally as 12 comprises two flexible sheets, each formed into a shapeof a cross, as shown, so that together they may form six panels asindicated, one panel 15 a forming the lid portion 14, four panels 15 bforming wall portions and one panel 15 c forming a base portion.

Although, in the embodiment shown in FIGS. 2 and 3, the barrier PCMlayers are shown formed in the shape of a cross, it will be appreciatedthat they could be formed in any of a number of shapes, which couldsimilarly be folded to line all six sides of the void formed by the coolpacks 9, 10, 11. Also, the container 1 may not be generally square inshape, as illustrated in FIG. 1, but it could for example berectangular. In this case the panels 15 a, 15 b and 15 c of the barrierPCM layers 12, shown in FIGS. 2 and 3, may not all be the same size. Inthis case, the vacuum insulation panel 6 of FIG. 1 may also be ofdifferent sizes, as may the cool packs 9, 10, 11. Alternatively,multiple vacuum insulation panels or cool packs may be used on each ofone or more pairs of opposite sides of the container.

With reference to FIG. 2, the barrier PCM layer 12 is formed by bondingtwo flexible sheets together to join them around their peripheral edge16. This may be by any known technique and may be by heat or radiofrequency welding. The envelope formed by the two laminated sheets maythen be filled with the phase change material Tetradecane.

The filled envelope is may then be further bonded, again by any knowntechnique which may be by heat or radio frequency welding, to formliving hinges 17 which define the six panels and permit them to beeasily folded relative to each other in order to line the main PCMlayer, comprising the cool packs 9, 10 and 11. This further bondingadditionally provides a number of smaller bonds 18 which provide thebarrier PCM layer 12 of FIG. 2 with a quilted effect, with the phasechange material within the envelope constrained in small pockets 19defined by the bonds 18, which ensure the phase change material remainsuniformly distributed throughout the barrier PCM layer 12.

In an alternative arrangement, and again with reference to FIG. 2, thebarrier PCM layer 12 could be created by thermoforming a lower laminatesheet, such as a polyamide/polyethylene laminate, of a semi rigidconstruction into a mould, to produce a plurality of 3 mm to 8 mm deeprecesses in the laminate which are subsequently filled with theTetradecane. A top film layer of the same or a similar laminate couldthen be positioned over the lower laminate and bonded by any knowntechnique, which may be heat or radio frequency welding, to form thesmall closed pockets 19 of FIG. 2 and to also create the living hinges17, which define the six panels and permit them to be easily foldedrelative to each other in order to line the main PCM layer, comprisingthe cool packs 9, 10 and 11.

Referring to FIG. 3, there is illustrated an alternative barrier PCMlayer 12 to that shown in FIG. 2. This may be formed from two vinylsheets, again formed in the shape of a cross as shown. Here though,before the vinyl sheets are bonded together to form the envelope of thebarrier PCM layer, six pouches are first formed. Each pouch comprises acapillary sheet 20 of a 6 mm thick woven polypropylene absorbent,sandwiched between two sheets of a polyamide/polyethylene laminate,which two laminated sheets are bonded together around their edges andfilled with Tetradecane before being sealed. The pouches may then beplaced between the vinyl sheets of the barrier PCM layer 12 before theenvelope of the barrier PCM layer 12 can is bonded around its peripheraledge 16 and in the region of the living hinges 17, shown in FIG. 3, toform the living hinges 17 and defining the six panels of the barrier PCMlayer 12, with the phase change material being evenly distributedbetween the panels 15 a, 15 b, 15 c.

As a further alternative, and again with reference to FIG. 3, thebarrier PCM layer 12 could be created by thermoforming a lower laminatesheet, such as a polyamide/polyethylene laminate, into a mould toproduce a plurality of 3 mm to 8 mm recesses, into each of which acapillary sheet 20 is placed before being filled with the Tetradecane. Atop film layer of the same or a similar laminate could then bepositioned over the lower laminate and bonded, by any known technique,which may be heat or radio frequency welding, to form closed cells andalso to create living hinges 17 which define the six panels and permitthem to be easily folded relative to each other, in order to line themain PCM layer, comprising the cool packs 9, 10 and 11.

The capillary action of the capillary sheets 20 ensures that the phasechange material is distributed relatively evenly through each of thepanels 15 a, 15 b, 15 c of the barrier PCM layer 12, even when these arearranged vertically, as for example in the case of the panels 15 b,which line the wall cool packs 9.

Referring again to FIG. 1, in use the cool packs 9, 10 and 11 formingthe main PCM layer and the barrier PCM layer 12 are removed from thecontainer 1 and the cool packs 9, 10 and 11 are chilled to around −18°C., in order to cause the phase change material within the cool packs 9,10 and 11 to release energy and transition to a solid state, whilst thebarrier PCM layer 12 is left at room temperature.

When it is desired to ship a product at a temperature which is to bemaintained in the range of 2° C. to 8° C., cool packs 9, 10 and 11 areplaced directly in the container 1 without the need to first let themwarm up. The barrier PCM layer 12, either as shown in FIG. 2, or asshown in FIG. 3, is then inserted into the container 1, as shown inFIG. 1. A product for transportation may then be placed in void 13, orthe void 13 may additionally be lined, for example with a corrugatedinsert, prior to a product being placed within the container 1. When theproduct has been placed in the container 1, the lid portion 14 of thebarrier PCM layer 12 is then closed and top cool pack 11 placed on top.A further vacuum insulation panel 22 is then placed on top of the topcool pack 11 and on top of this is placed a lid 23 of expandedpolystyrene. Alternatively, the further vacuum insulation panel 22 maybe housed in the lid 23 of expanded polystyrene 23. The flaps 3 and 4 ofthe outer box 2 are then closed and the container 1 is ready forshipping.

The product, to be maintained in the temperature range 2° C. to 8° C.,is protected from the initial extreme cold of the cool packs 9, 10, 11by the barrier PCM layer 12. The phase change energy of the PCM materialin the barrier PCM layer is in the range of 12% to 22% of the phasechange energy of the PCM material in the main PCM layer 9, 10, 11. Thisis sufficient to enable the barrier PCM layer 12, via the latent heat offusion of the phase change material within the barrier PCM layer 12, toprovide energy (“sensible heat”) to the main PCM layer to bring it up tothe temperature at which a phase change occurs, normally about orslightly above 5° C. Thus the temperature of the barrier PCM layer 12does not drop below this temperature and thus the barrier PCM layer 12protects a product from being overly chilled. Furthermore, the uniformdistribution of the phase change material, in the barrier PCM layer 12,ensures that the product does not experience any localised cold spots.

The present invention has been described with reference to the Figures,by way of example only. It will be appreciated that many modificationsmay be made which fall within the scope of the invention as defined bythe following claims.

1. A thermally insulated container comprising: a thermally insulatinglayer defining a first void; a main PCM layer containing phase changematerial and located within the first void and defining a second voidwithin the first void; and a barrier PCM layer containing phase changematerial and located within the second void and distinct from the mainPCM layer, the barrier PCM layer having an average thickness anddefining a third void within the second void; the container beingarranged to receive a product for transportation inside of the thirdvoid; wherein the main PCM layer has an average thickness greater thanthe average thickness of the barrier PCM layer; the barrier PCM layercomprises an envelope in which the phase change material of the barrierPCM layer is relatively evenly distributed; and wherein the barrier PCMlayer further comprises a capillary sheet within the envelope, whichcapillary sheet is formed of a material which exhibits a capillaryaction on the phase change material within the envelope.
 2. Thethermally insulated container as claimed in claim 1, wherein the barrierPCM layer is configured to maintain the phase change material with arelatively even distribution within the envelope by the envelope havinga quilted configuration, by being divided into a plurality of discretepocket each pocket containing a volume of the phase change material. 3.The thermally insulated container as claimed in claim 2, wherein theenvelope is formed from two sheets of flexible material bonded togetherto divide the envelope into the plurality of discrete pockets. 4.(canceled)
 5. The thermally insulated container as claimed in claim 1,wherein the capillary sheet within the envelope is between 3 mm and 6 mmthick.
 6. The thermally insulated container as claimed in claim 2,wherein the envelope is formed from two sheets of flexible materialbonded together and with the capillary sheet therein.
 7. The thermallyinsulated container as claimed in claim 6, wherein the envelope houses apouch containing the capillary sheet and phase change material.
 8. Thethermally insulated container as claimed in claim 1, wherein the mainPCM layer comprises one or more packs containing phase change material,which packs are formed of a different material to the envelope and aresubstantially more rigid than the envelope.
 9. The thermally insulatedcontainer as claimed claim 1, wherein the main PCM layer comprises aplurality of packs, each pack containing phase change material, whichpacks are formed of a different material to the envelope and aresubstantially more rigid than the envelope, with packs corresponding toeach of four sides and a base of the container.
 10. The thermallyinsulated container as claimed in claim 9, wherein at least two of thepacks are separate from each other.
 11. The thermally insulatedcontainer as claimed in claim 1, wherein the barrier PCM layer comprisesat least four joined together envelopes, one corresponding to each offour sides of the container.
 12. The thermally insulated container asclaimed in claim 1, wherein the barrier PCM layer comprises at leastfive joined together envelopes, one corresponding to each of four sidesand a base of the container.
 13. The thermally insulated container asclaimed in claim 1, wherein the barrier PCM layer comprises at least sixjoined together envelopes, one corresponding to each of four sides ofthe container, one to the base and one to a lid of the container. 14.The thermally insulated container as claimed in claim 11, wherein eachof the envelopes is joined to an adjacent envelope by being welded tothat envelope.
 15. The thermally insulated container as claimed in claim11, wherein all the envelopes are formed from two sheets of flexiblematerial bonded together to define said envelopes, with the bondsforming living hinges to permit adjacent envelopes to be folded relativeto each other to a shape substantially corresponding to that of thesecond void of the container.
 16. The thermally insulated container asclaimed in claim 3, wherein the two sheets of the envelope are eachformed from a polyamide and polyethylene laminate with the two sheetsbeing bonded together by being heat welded.
 17. The thermally insulatedcontainer as claimed in claim 1, wherein the phase change material ofthe main PCM layer is the same as the phase change material of thebarrier PCM layer.
 18. The thermally insulated container as claimed inclaim 1, wherein the latent heat of fusion of the phase change materialmultiplied by the volume of the phase change material of the barrier PCMlayer is between 8% and 36% of the latent heat of fusion of the phasechange material multiplied by the volume of the phase change material ofthe main PCM layer.
 19. The thermally insulated container as claimed inclaim 1, wherein the latent heat of fusion of the phase change materialmultiplied by the volume of the phase change material of the barrier PCMlayer is between 12% and 22% of the latent heat of fusion of the phasechange material multiplied by the volume of the phase change material ofthe main PCM layer.
 20. The thermally insulated container as claimed inclaim 1, wherein the thermally insulating layer comprises a layer ofexpanded foam and is lined with vacuum insulation panels located withinthe first void, each vacuum insulation panel having an inner facingsurface, an upper edge and an outer facing surface.
 21. (canceled) 22.(canceled)
 23. (canceled)
 24. (canceled)
 25. (canceled)
 26. (canceled)27. (canceled)
 28. (canceled)
 29. (canceled)
 30. The thermally insulatedcontainer as claimed in claim 20 and further comprising: a sheet toprotect the vacuum insulation panels, the sheet configured to line atleast part of the inner facing surface, the upper edge and at least partof the outer facing surface of each vacuum insulation panel.